Difficult Embryo Transfer: A Systematic Review

Cervical Stenosis After Hysteroscopic Surgery for Cesarean Scar Disorder

Cesarean scar disorder (CSDi) is a newly recognized cause of secondary infertility. Laparoscopic or hysteroscopic surgery is generally chosen for the surgical treatment of CSDi, depending on the residual myometrial thickness of the cesarean scar. Previously, hysteroscopic transcervical resection for CSDi (TCR-CSDi) has been reported to be a safe procedure, with no cases of postoperative cervical stenosis. Herein, we report a novel case of cervical stenosis after circumferential hysteroscopic TCR-CSDi of an extensive CSDi lesion. Notably, although no cervical stenosis was observed upon postoperative hysteroscopy one month postoperatively, cervical stenosis developed four months after the surgery; therefore, it is important to avoid circumferential resection and cauterization in patients with CSDi, even when abnormal blood vessels are present. Additionally, it is advisable to check for delayed cervical stenosis at least three weeks before embryo transfer in patients who have undergone TCR-CSDi.

Embryo Transfer Procedural Parameters Do Not Predict IVF Cycle Outcome

BACKGROUND

this study aims to assess the effect of embryo transfer (ET) performance parameters of a technical nature on IVF outcome.

METHODS

A total of 1417 ETs from a single IVF center were included in this prospective observational study. The parameters investigated were as follows: the presence of cervical mucus post catheter withdrawal, the presence of blood, catheter reload, the employment of a tenaculum and stylet, catheter resistance as experienced by the physician and patient discomfort.

RESULTS

When ET performance parameters were associated with clinical outcomes on a singular level, none of the ET parameters presented with any statistical significance. The evaluation of covariates indicated that the number and the quality of transferred embryos, as well as maternal age, exerted a statistically significant effect on clinical outcomes. In a multivariate analysis, only the presence of mucus along with significant catheter resistance presented with statistical significance; however, when adjusting for covariates, this combination showed no statistically significant effect on clinical outcomes.

CONCLUSIONS

the results indicate that the time-consuming process of recording and analyzing ET performance parameters fails to offer any additional value in predicting the cycle's outcome, while factors like embryo quality and number, as well as maternal age, seem to be the sole robust predictive factors of an IVF cycle.

Evidence and consensus on technical aspects of embryo transfer

BACKGROUND

Ultrasound-guided embryo transfer (US-GET) is a widely performed procedure, but standards for the best practice are not available.

OBJECTIVE AND RATIONALE

This document aims to provide an overview of technical aspects of US-GET after considering the published data and including the preparation for the embryo transfer (ET) procedure, the actual procedure, the post-procedure care, associated pathologies, complications and risks, quality assurance and practitioners’ performance.

SEARCH METHODS

A literature search for evidence on key aspects of the ET procedure was carried out from database inception to November 2021. Selected papers (n = 359) relevant to the topic were analysed by the authors. The following key points were considered in the papers: whether ultrasound (US) practice standards were explained, to what extent the ET technique was described and whether complications or incidents and how to prevent such events were reported. In the end, 89 papers could be used to support the recommendations in this document, which focused on transabdominal US-GET.

OUTCOMES

The relevant papers found in the literature search were included in the current document and described according to the topic in three main sections: requirements and preparations prior to ET, the ET procedure, and training and competence for ET. Recommendations are provided on preparations prior to ET, equipment and materials, ET technique, possible risks and complications, training and competence. Specific aspects of the laboratory procedures are covered, in particular the different loading techniques and their potential impact on the final outcomes. Potential future developments and research priorities regarding the ET technique are also outlined.

LIMITATIONS, REASONS FOR CAUTION

Many topics were not covered in the literature review and some recommendations were based on expert opinions and are not necessarily evidence based.

WIDER IMPLICATIONS

ET is the last procedural step in an ART treatment and is a crucial step toward achieving a pregnancy and live birth. The current paper set out to bring together the recent developments considering all aspects of ET, especially emphasizing US quality imaging. There are still many questions needing answers, and these can be subject of future research.

STUDY FUNDING/COMPETING INTEREST(S)

No funding. ADA has received royalties from CRC Press and personal honorarium from Cook, Ferring and Cooper Surgical. The other co-authors have no conflicts of interest to declare that are relevant to the content of this article.

Intra-cavitary fluid resulted from caesarean section but not isthmocele compromised clinical pregnancy after IVF/ICSI treatment

The aim of this study was to explore whether the presence of intra-cavitary fluid (ICF) influences the pregnancy outcomes of patients with caesarean section (CS) in embryo transfer cycles. A total of 8494 transferred cycles of 4924 women were enrolled in this retrospective study and separated into three subgroups by previous delivery method and the presence of intra-cavity fluid, a caesarean group with ICF (CS-ICF, n = 649), a caesarean group without ICF (CS-noICF, n = 3207), and the remaining 4638 cycles without ICF were included in the vaginal delivered group (VD, n = 4638). Baseline characteristics and clinical outcome were compared. Propensity score matching (PSM) was conducted to adjust confounding factors between groups. Patients in the CS-ICF group were of younger age (36.49 ± 4.19 vs 37.34 ± 4.25, 37.32 ± 4.86, P < 0.001), had better ovary reserve, and had more blastocyst transferred compared with the CS-noICF and VD groups. However, cycles in the CS-ICF group achieved unsatisfactory clinical pregnancy outcomes. PSM analysis for comparability and differences in clinical outcomes still existed. The clinical pregnancy rate was significantly lower in the CS-ICF group than in the CS-noICF group (35.1% vs 41.7% for CS-noICF group, 48.1% for VD group, P < 0.001). Subgroup analysis of fresh embryo transferred cycles, the differences in clinical outcomes disappeared after PSM analysis, while the clinical pregnancy rate was still lowest among the three matched groups of FET cycles (36.4% vs 50.3% for VD group, P < 0.001). The presence of intra-cavitary fluid (ICF), but not necessarily the isthmocele, significantly compromises the clinical pregnancy rate in patients with previous CS undergoing IVF/ICSI treatment.

Evaluation of a strategy for difficult embryo transfers from a prospective series of 2,046 transfers

Objective

To evaluate an embryo transfer strategy for difficult transfers (DiTs).

Design

Prospective, nonrandomized, observational, cohort study

Setting

A hospital fertility center in France.

Patient(s)

Data were collected on all embryo transfers conducted using the strategy between February 2014 and February 2020.

Intervention(s)

Anatomical characteristics that could cause DiT were identified by transvaginal ultrasound and the catheter was adapted accordingly. Transfer was guided by transvaginal ultrasound. After passage through the cervix, a rest period was introduced to allow any contractions to stop before embryo deposition in the uterus.

Main Outcome Measure(s)

The primary criterion was the percentage of pregnancies per transfer (P/T) after an easy transfer (EaT) or a DiT. The secondary criteria included the anatomical causes of DiT and the patients’ levels of discomfort.

Result(s)

Of 2,046 transfers, 257 (12%) were DiTs: minor difficulties (n = 152; 7.4%), major difficulties (n = 96; 4.7%), very significant difficulties (n = 7; 0.3%), or impossible (n = 2; 0.1%). The most common causes of DiTs were endocervical crypts (54%), tortuous cervical canal (36%), and marked uterine anteversions (30%). Several causes were often responsible for DiTs. There was no statistically significant difference in the P/T between the EaTs (n = 1,789, 41%) and all degrees of DiT (n = 257, 37%). In addition, there was no statistically significant difference between the level of patient-reported discomfort in the EaT and DiT groups.

Conclusion(s)

This study demonstrated that an adapted embryo transfer strategy, monitored by transvaginal ultrasound, led to similar pregnancy rates regardless of whether the transfer was easy or difficult.

Cervical stenosis and pregnancy rate after ultrasound guided cervical dilation in women undergoing saline infusion sonography

Aim

To assess the effect of ultrasound-guided cervical dilation on clinical pregnancy rates in women with cervical stenosis.

Methods

A prospective case control study was conducted in women with unexplained infertility. These women underwent saline infusion sonography and were suspected of having cervical stenosis if a 7 French Foley’s catheter could not be introduced into the cervical canal. Women with suspected stenosis who agreed to undergo ultrasound guided dilation were included as cases. Those with suspected stenosis who refused dilation were used as controls. Both groups were followed for one year. The primary outcome measure was women who had clinical pregnancy i.e. fetal heart beat present on transvaginal scan during the follow up period.

Results

During the study period, 1097 women who underwent SIS were included. A total of 117 (10.7%) patients had cervical stenosis. No statistically significant difference was there in both groups in terms of mean age (p = 0.617), mean body mass index (p = 0.598), duration of infertility (p = 0.588) and type of infertility (p = 0.167). However, both groups were significantly different in terms of history for risk factors i.e. endometriosis (p <0.001), prior surgery (p <0.001), polyps (p = 0.004) and pelvic inflammatory disease (p = 0.001). Eighty-nine women agreed to have dilation and were used as cases and 28 women refused and were used as controls. Of the cases, 70.45% conceived as compared to 18.5% of controls. The mean time to conception in months was also significantly lower in cases (8.10 ± 3.43 vs. 11.39 ± 1.97, p <0.001).

Conclusions

Our study shows that ultrasound-guided cervical dilation in women with cervical stenosis can lead to improved conception rates.